The present invention relates generally to floating decanters for a wastewater treatment facility and, in particular, to such decanters having mooring arms pivotally connected to a wall of a reactor basin and flexible discharge manifolds equipped with valve mechanisms that seal the discharge manifold against fluid flow from the basin during periods of agitation and mixing of the wastewater.
Certain wastewater treatment processes, especially those utilizing sequenting batch reactor techniques or processes, require that clarified fluid be periodically withdrawn from the reactor or digester within which the process is occurring. Decanters that are utilized to remove the clarified fluid from the reactor are often mounted on a float that buoyantly supports the decanter. A support system is typically included to retain the float an decanter in a particular area and yet allow the decanter and float to move in a vertical direction as the water level in the basin changes.
Some decanter and float support systems include vertical support posts mounted on the basin floor that are slidingly connected by support hardware to the float and decanter. The float and attached decanter slide vertically as the water level changes in the basin. A drawback of such a support system is that the vertical posts are subjected to a torque or twisting force when fluid enters the reactor and when the fluid is mixed therein. This twisting force is transmitted to the decanter and float through the length of the post, thereby intensifying this torque and reducing the life expectancy of the post supports and support hardware. Secondly, such devices require an operator to voyage to the float and decanter for maintenance or retrieval. This may be dangerous, as well as inconvenient. Finally, a decanting apparatus moored on posts in a central portion of a basin requires additional floats for buoyantly supporting a line that provides power to an actuator for opening and closing the decanter. The power line is exposed to the corrosive waste or liquid within the tank which not only causes difficulty in cleaning, but may reduce the life expectancy of the line.
Other decanter and float support systems include a rigid support structure that surrounds a flexible discharge conduit connected to the decanter. Such a support structure is mounted on a wall of the basin and includes sections that hinge so that the conduit may pivot or flex as the water level in the basin increases or decreases. A drawback of such a support system is that an operator must also make the inconvenient and sometimes dangerous voyage to the float and decanter for maintenance or retrieval. If it is desired to utilize a decanter having a power-actuated valve for drawing in liquid, such a support system may not provide the rigidity necessary to keep the decanter in place during the turbulent mixing cycle of a reactor. Such a support system may also require additional floats for buoyantly supporting a power line if a power actuator is used. In the alternative, such a power line may be attached to the support system and flexible conduit. However, the support system and conduit are below the fluid level, therefore both the system and power line may be awkward and troublesome to maintain.